Bulimia nervosa and binge eating disorder are marked by significant levels of impairment and psychiatric comorbidity, affecting approximately 5-7% of the US population. Guided self-help cognitive behavioral (CBT-GSH) therapy has been show to be an effective treatment to reduce binge eating for patient with both disorders. However, there is limited uptake among both clients and therapists. One significant factor is self-monitoring, the central component of cognitive- behavioral therapy, which is both time-intensive and cumbersome in its traditional paper format for clients, as well as difficult to comprehensively address in a time-limited session for the therapist. This grant proposes to utilize emerging mobile application technology, as a tool for increasing the potency, accessibility, and efficacy of guided self-help. This will be accomplished by adapting WorkSmart Lab's current commercial mobile product for healthy eating and exercise, Noom Monitor, into a self-monitoring application integrating CBT-GSH tools for binge eaters. Additionally, the application will be used to facilitate real-time feedback to therapists about their patient progres. Therapists will be notified in real-time about any drastic changes in client eating patterns through pre-set alerts designed to assign a grade to therapists, representing each client's well-being. The feasibility and efficacy of the adapted Noom Monitor application will be examined through a randomized control trial comparing CBT-GSH + APP with CBT-GSH conducted at the Mount Sinai School of Medicine's Eating and Weight Disorders Program. The innovative utilization of technology to assist in mental health interventions has widespread implications outside of this proposal, which will be used to strategize the further development and commercialization of this product.